How to defeat the last boss
Before you go down make sure you break all the boxes for full life. Then get the blue eco and go down and fight. What you have to do first is get the yellow eco and shoot at its eye. Now the giant robot will shoot things into the dark eco and lurkers will come out. Keep your distance from them and shoot at them with the yellow eco. (Close up attacks won't work because you will get hurt). Once you defeat all of them, get yellow eco and shoot at the robot again. Now the robot will shoot little red balls out. They will explode rings. Jump over all the rings. Now get yellow eco and shoot at the robot again. Now the robot will start shooting yellow beams at you dodge those and get yellow eco and shoot at the gun it is firing with. Now white eco will appear. Bombs will be shot at the ground but just ignore them. Wait for the white eco to appear on the ground and get it. Now you won the fight.